Which chip did I just blow up? NEC D65654GMY09

[MattAtStanford]

I'm trying to figure out how an overvoltage got behind my opto-isolators when I was working on a digital circuit. Two pins on the NEC D65654GMY09 are fried off the trace. It would help to know what the chip does and what the pins 60 and 61 do (counting clockwise from the short corner).

[sergesl]

Hello Matt,
That's a good question to address to NEC or to answer by getting the NEC D65654GMY09 datasheet that we unfortunately do not have. However, even with opto isolators, you can still have a high enough voltage to break the isolation kind of like a capacitor. I am not sure though how much voltage you have, but everything depends on how the NEC D65654GMY09 is built.
Sorry we cannot be of more help. Good luck with your project...

[MattAtStanford]

Any idea what this chip does on the NI board? I relize its a big chip, but does anyone know why NI put it on there?

I found these data sheets, just in case you want a copy.
Overview: http://www.ee.nec.de/_pdf/A10013EE2V0DS00.PDF
Design guide with pinouts: http://www.ee.nec.de/_pdf/A10137EJCV1UM00.PDF

[shoneill]

Hi Matt,

could the overvoltage have come from "behind" the opto-isolation? I mean, the chip has a power requirement, maybe THIS caused the problem.......

Shane.

[sergesl]

Hi Matt,

I did not realize this before, but the NEC chip you mentioned is actually one of the components of our devices. Below is useful information about possible reasons of the overvoltage.

The DAQ-STC is exposed via the Programmable Function Input (PFI) pins and the Digital Input/Output (DIO) pins. The PFI lines provide a configurable user interface to board via input, output, and internal routing of timing, trigger, and control signals. They have a maximum sink current of 9mA and source current of 5mA. The DIO lines are high-current bi-directional digital I/O lines for use in static I/O applications and have a maximum sink current of 24mA and source current of 13mA. Causing a current greater than these maximum values or driving the board while it is powered down will overdrive the DAQ-STC that could result in permanent damage the chip.

Because this chip has direct exposure to external connections, it can be easily damaged by misuse. Applying as little at 0.5V over the expected maximum voltage of 5V (5.5V) can destroy the chip. This can be done inadvertently during handling of the board by Electro-Static Discharge (ESD) or by operating the board with bent pins causing shorts between and of the PFI or DIO lines. Shorting any of these pins to the +5V or GND pin or driving the digital output lines when shorted will also cause damage to the chip. Below is an example of the damage that can be caused by this kind of misuse.

To prevent this, read below:

- Protect the inputs from over-voltage conditions. To do this you can use high voltage signal conditioning equipment such as the SCXI-1125 or SCC-AI0x. You can also use fuses for high voltage protection but be sure to check the speed rating of the fuse.

- When handling the device, use ESD protective systems and do not touch the connector pins.

- Before connecting the cable to the DAQ board or the source, be sure to check the connector for bent pins that could potentially cause a short.

- Power down external circuitry before powering down device.

[marles]

I would need a datasheet of this component too! I just blew up one digital line from my NI PCI-6723 card. 😞

Thank you.

Regards,

Paul T.